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  • From: Neil Bertrando <neilbertrando@gmail.com>
  • To: permaculture <permaculture@lists.ibiblio.org>
  • Subject: Re: [permaculture] Invasive species reconsidered
  • Date: Fri, 25 Feb 2011 21:18:19 -0800

Jono,

I very much appreciate your thoughtful article on this subject.

> Undoubtedly, we are responsible for the cataclysmic changes we’ve wrought,
> and we can’t place the blame anywhere else

This statement stands out to me. I think we often minimize the movement of
humans throughout the world and our effects on community dynamics and
ecosystems as an integral part of the 'invasive species' perspective.

For example, how long have humans been on North America? Caucasians?

consider the juxtaposed images of suburban sprawl, monoculture farmscapes
and monoculture 'invasive species' landscapes. We often speak of invasive
species, but what about invasive industry?

from a cause and effect perspective, could the true cause of 'invasion' be
our relationship with the ecology we participate in and our current systems
of management.

I have found the Holistic Management approach of focusing on ecosystem
processes as indicators of landscape health is very beneficial for my
perception of how we choose to treat invasive weeds in managed landscapes.
By considering the system as a whole, we can assess to what degree an
invasive species affects our ability to achieve our desired management goals
rather than putting emphasis on 'eradication' and 'wars on weeds'.

This 'war' based mentality fuels the profits of the 'war-profiteers' who
manufacture herbicides, as well as reinforcing an oppositional relationship
between us as humans and the 'rest of the world'.

I appreciate the attitudes of cooperation and positivity that are fostered
in this forum, and hope they can spread as we find more effective ways of
articulating these paradigms and applying them in our careers and life
paths.

best to all,
Neil

On Thu, Feb 24, 2011 at 7:32 PM, Jono Neiger <neiger@csld.edu> wrote:

> Here's an article I recently penned.
>
>
> Invasive Species: Some Science and Some Questions
> > FEBRUARY 15, 2011
> > in INVASIVE PLANTS<
> http://www.ecolandscaping.org/category/invasive-plants/>
> >
> > *by Jono Neiger*
> >
> > *“Man is part of nature, and his war against nature is, inevitably, a war
> > against himself.” *Rachel Carson, *Silent Spring, 1962***
> >
> > Invasive species, the new species on the block, have been taking heat for
> > ecosystem changes for several decades. And yet, many of our commonly held
> > assumptions about invasive species are not entirely correct. The science
> > backing up heated claims is increasingly coming into question. As
> ecological
> > designers, land managers and landscapers we rely on the information we
> get
> > to inform and direct our work.
> >
> > Many of us spend large amounts of time getting plants established,
> > maintaining plants, or managing woodlands, edges, and meadows. This is
> hard
> > work and not made any easier by the tough plants that may already be
> > occupying that space. Observation of invasive species where we live and
> work
> > seems to confirm our suspicions that they are rapidly taking over.
> >
> > *Early Control Strategies*
> >
> > I first took up the cause of fighting invasive species while restoring
> > riparian forest for The Nature Conservancy on the Sacramento River in
> > California in the early 1990s. Establishing forests in flood prone
> > agricultural fields was difficult but rewarding. Like farming crops,
> > establishing riparian species required controlling the weeds. We took
> that
> > task seriously and used mowing and hand removal, but mostly we used an
> ATV
> > spray rig to apply Roundup along the rows of plants. These weren’t just
> any
> > weeds; we had star thistle, bane of the west; Johnson grass with 6’-long
> > rhizomes; and numerous others. After several years I had been inoculated
> > with the fervor of fighting the battle to get our plants in, and the bad
> > ones out.
> >
> > <
> http://www.ecolandscaping.org/wp-content/uploads/2011/02/neiger-photo-1.200.jpg
> >
> > The Nature Conservancy restoration project on the Sacramento River 18
> years
> > later.
> >
> > These projects were very successful. I recently had the chance to visit
> two
> > of the fields we planted about 18 years ago. Our plantings of seeds,
> starts,
> > and cuttings are now a forest. The stately valley oaks are now big enough
> > that my 13-year-old son could climb them. We saw the massive ten feet
> tall
> > elderberry bushes and towering willow and cottonwood trees over 30 feet
> > tall. I was moved to see the results of our sweat and toil. A deer ran
> from
> > us as we climbed over fallen wood and worked through brush and limbs. I
> > found drip line still there, though the rows were now hard to make out
> > through the new growth established among the intentional plantings.
> >
> > But the strategies we used were very expensive and energy intensive. They
> > relied on a complete domination of the land the same as the farming
> > practices we mimicked. Since that time much of the project focus has been
> to
> > buy up floodplain land and allow natural systems and succession to
> establish
> > floodplain forest.
> >
> > In the years since planting that forest, I have spent many hours trying
> to
> > understand the feelings that grew in me while we fought the weeds and
> > established “our” plants. When I left the project, I had a passion and
> > fervor for native plants that remains with me. I also had adopted a
> > missionary zeal fueled with anger. In my desire to help natural systems,
> I
> > found myself at war with a part of it. In the war to heal nature, I felt
> > that invasive plants were the problem.
> >
> > *Reassessing and Questioning*
> >
> > I lost this zeal and anger several years later when a teacher kindly and
> > persistently kept asking what those plants had done to me personally. I
> was
> > ripping out Scotch broom from a planting we had completed to diversify an
> > orchard into a forest garden. (My teacher kept replanting them….) The
> > proverbial light bulb went off as I saw myself angrily pulling those
> plants
> > out, believing I knew better how to heal the disrupted landscape we
> worked
> > in. Suddenly, I felt less sure of myself and full of questions.
> >
> > <
> http://www.ecolandscaping.org/wp-content/uploads/2011/02/neiger-photo-2.200.jpg
> >
> > The Nature Conservancy project revisted.
> >
> > Those questions sent me looking to better understand restoration work,
> the
> > ecology of disturbed landscapes, the ecology of invasive plants, and the
> > reason these newly arrived species are so different. As a pioneer
> species,
> > the Scotch broom in the forest garden we planted was fixing nitrogen and
> > stabilizing the poor, clayey soils. How was this process different than
> > succession in the woods nearby? Why didn’t it belong there? Was it a
> problem
> > or a solution? Did succession still operate here and what about
> disturbance
> > ecology? Were other species helped or harmed by the Scotch broom?
> >
> > I have since come to have more questions than answers about invasive
> > species. Questions like: How do we separate invasive species effects from
> > climate change, habitat loss, development, sprawl and human population
> > impacts? What objective ecological criteria identify “alien species” or
> > “invaders”? What are the temporal and spatial scales included in the
> > definitions? What protocols will determine the conservation value of new
> > species populations that have moved outside their “historical ranges”?
> > Should we consider the mere existence of an allegedly nonnative species
> > sufficient evidence for control or extermination? On what factual basis
> can
> > we take this position?
> >
> > Close observation and good research is required to understand the
> > ecological implications of the changed ecosystems around us. I’ve also
> > looked closely at the emotional reactions of myself and others to the
> > changes in species and ecosystems. The changes we humans are witnessing
> (and
> > causing) are vast. There is no doubt that we are losing species and
> habitat;
> > that the climate is changing, getting more extreme; that soils are
> eroded,
> > compacted, and made toxic; that waterways are polluted; that wells are
> > drawing precious groundwater up faster than it can be replenished; that
> > species are being moved far from where they originated; and that the
> ground
> > itself is covered over, sealed in a casing of asphalt and concrete.
> >
> > *Defining the Battle Against Invasive Species*
> >
> > It’s change on a scale we can’t imagine. And of course we want to find a
> > way to stop it. And find who or what is responsible. Enter the battle
> > against Invasive Species.
> >
> > Charles Elton wrote *The Ecology of Invasions by Animals and Plants
> *in**1958,
> > using colorful language and metaphor. He essentially started the field of
> > Invasion Biology writing this book. Elton conceived the introduction and
> > spread of non-native species as ecologically distinct from native species
> > dispersal and colonization. After defining invasion biology this way, the
> > field has retained the concepts of invasive species as different and of
> the
> > invasion process as different from succession ecology and disturbance
> > ecology. Forty-three years later, Davis, Thompson, and Grime looked at
> > research citation practices and concluded that the field of Invasion
> Biology
> > had dissociated itself from succession ecology and other ecological
> > sub-disciplines (Davis et al. 2001). This distinction between native
> > colonizers and introduced invaders is likely spurious and a hindrance to
> > further understanding the processes of introduced species.
> >
> > There is no disputing that newly arrived species can, and in many cases
> do,
> > bring dramatic and alarming changes to ecosystems. Islands like Guam and
> > Hawaii have been hard hit from the brown tree snakes and goats, pigs,
> rats,
> > and cows respectively. Thousands of species have been moved long
> distances
> > and are changing ecosystems in known and unknown ways. Many scientists
> are,
> > however, finding the ecosystem picture far from black and white. Early
> > observations and conclusions are not proving out. Not all interactions
> are
> > negative and many are positive.
> >
> > As an example, zebra mussels colonized the great lakes and Hudson River
> > estuary in the early 1990s. Predictions were dire and indeed they have
> cost
> > industry money to clear intake pipes and outfalls. But the ecological
> > impacts are harder to gauge and continue to unfold over time. Numerous
> > studies show the mussels have dramatically changed water quality
> parameters,
> > reducing chlorophyll and phosphorous levels and increasing transparency
> in
> > these highly polluted waters (for instance Fahnenstiel 1995). A cascade
> of
> > changes in the aquatic food web has ensued. Though phytoplankton levels
> are
> > down, many reduced fish stocks have returned. In Long Point Bay, Ontario
> > researchers found the introduced mussels are providing food for three
> duck
> > species increasing waterfowl activity 10-fold (Strayer 2006). These
> aquatic
> > systems were in a state of decline from decades of eutrophication, water
> > contamination, and species loss. Some species have rebounded, but others
> > still struggle. The ecological effects of the zebra mussel are not all
> bad.
> > Ecological systems are profoundly dynamic and in many places newly
> > introduced species are adding to the change in ways that can be hard to
> > understand.
> >
> > *The Extinction Quandary*
> >
> > One commonly held (and perpetuated) claim about invasive species is
> highly
> > questionable. The claim is that “Invasive species are the second leading
> > cause of extinctions”. This declaration was made in an assessment of data
> > sets and personal interviews by David Wilcove and others and published in
> a
> > 1998 paper titled “Quantifying Threats to Imperiled Species in the United
> > States”. The assessment had serious limitations including partial
> available
> > data; use of anecdotal accounts; and inclusion of Hawaii, whose distinct
> > conditions greatly skewed the data. The authors themselves stated the
> > limitations to their data. But the paper is widely cited in other
> scientific
> > papers (over 700 times in the ten years following publication), research
> > proposals, and college classes. In the media the claim of invasive
> species
> > as the second leading cause of extinctions is presented as fact
> (sometimes
> > attributing invasive species to extinctions globally), and often the link
> to
> > where it came from is left off completely. Several authors have
> reassessed
> > the data and found the link between invasive species and species
> extinction
> > lacking:
> >
> > *“The link between species invasions and the extinction of natives is
> > widely accepted by scientists as well as conservationists, but available
> > data supporting invasion as a cause of extinctions are, in many cases,
> > anecdotal, speculative and based upon limited observation.” (*Gurevitch
> > and Padilla 2004)
> >
> > A study in Canada analyzing extinction threats found introduced species
> to
> > be the least important of the six categories analyzed: habitat loss,
> > over-exploitation, pollution, native-species interaction, introduced
> > species, and natural causes such as stochastic events like storms and
> > limited dispersal ability (Venter 2006).
> >
> > Many questions about invasive species need to be answered. Are
> naturalized
> > species the drivers or passengers of change? Are the long-term effects
> > negative? Do human-caused invasions differ significantly than “natural”
> > invasions? How do we measure harm and how is harm different from change?
> How
> > do we separate invasive species effects from climate change, habitat
> loss,
> > development, sprawl, and human population impacts? Scientists are
> grappling
> > with these questions. Notably, Dr. James Brown, Distinguished Professor
> of
> > Biology at the University of New Mexico and Dr. Dov Sax, Assistant
> Professor
> > at the University of Georgia’s Institute for Ecology, have wrestled with
> the
> > relationship of invasive species and ecosystems.
> >
> > *“We don’t know how serious the threats of alien invaders are to our
> > native flora and fauna; these are scientific questions. And, as is often
> the
> > case in science, the answer is less clear than reports in the popular
> press
> > about the devastating impacts of gypsy moth, zebra mussels, and purple
> > loosestrife might imply…. Although we often accuse invasive species of
> > damage to the structure and function of ecosystems, there is usually
> little
> > hard scientific evidence of such negative impacts.” *(Brown et al.
> 2007)**
> >
> > *An Ongoing Discussion*
> >
> > At the ELA Conference on March 3rd, I will participate in a panel
> > discussion that allows time to delve into more of the research and
> differing
> > perspectives on invasive species as well as what land management
> approaches
> > we might take. I hope to engage people in discussion that will bring more
> > consideration to this difficult topic. I know that many people have
> strong
> > feelings about invasive species. Some feel certain in their approach and
> > others are searching for more understanding. There are no easy answers.
> >
> > Undoubtedly, we are responsible for the cataclysmic changes we’ve
> wrought,
> > and we can’t place the blame anywhere else. In the years since I planted
> > trees on the Sacramento River I have learned that we can be a positive
> part
> > of this process. We need clear thinking, solid research with quality peer
> > review to help direct our management activities. Anything less is wasting
> > our time and efforts and imperiling fragile ecosystems.
> >
> > Copyright © 2011, Jono Neiger
> >
> > *About the Author*
> >
> > *<
> http://www.ecolandscaping.org/wp-content/uploads/2011/02/jono_neiger.100.jpg
> >Jono
> > Neiger* worked as a restoration biologist with the Nature Conservancy for
> > several years, establishing riparian forest on the floodplain of the
> > Sacramento River in California. Jono is an ecologist/land
> manager/landscape
> > designer, teaches permaculture design at the Conway School of Landscape
> > Design, and operates a design and implementation firm, Regenerative
> Design
> > Group in Greenfield, Massachusetts.
> >
> > Jono, William Cullina, and Peter Del Tredici will engage in a panel
> > discussion entitled “Native, Introduced, Invasive, and Endangered Plants
> in
> > the Landscape: Untangling the Roots of the Problem” on March 3 at the ELA
> > Conference <http://www.ecolandscaping.org/conference/>&
> Eco-Marketplace.
> > Jono may be found at http://regenerativedesigngroup.com.
> >
> > *References:*
> >
> > Brown, J. H., D. F. Sax, D. Simberloff, M. Sagoff 2007. “Aliens Among
> Us.”
> > *Conservation Magazine*, (8)2:14-21.
> >
> > Colautti, R.I., and H.J. MacIsaac 2004. “A neutral terminology to define
> > ‘invasive’ species.”* Diversity and Distributions*, (10):135-141.
> >
> > Davis, M., K. Thompson, and P. Grime 2001. “Charles S. Elton and the
> > dissociation of invasion ecology from the rest of ecology.”*Diversity and
> > Distributions, *(7):97-102
> >
> > Davis, M. 2009. “*Invasion Biology*” Oxford University Press.
> >
> > Fahnenstiel et al. 1995. “Effects of zebra mussel (*Dreissena
> polymorpha*)
> > colonization on water quality parameters in Saginaw Bay, Lake Huron.”
> *Journal
> > of Great Lakes Research*, (4):21
> >
> > Gurevitch, J. and G. Padilla 2004. “Are invasive species a major cause
> > of extinctions?” *Trends in Ecology and Evolution*, (19):9
> >
> > Strayer et al. 2006 “Understanding the long-term effects of species
> > invasions”, *Trends in Ecology and Evolution*, (21):11
> >
> > Venter, B. et al. 2006. “Threats to endangered species in Canada.”*
> > Bioscience*, (56):903-910
> >
> > Wilcove et al. 1998. “Quantifying threats to imperiled species in the
> > United States: Assessing the relative importance of habitat destruction,
> > alien species, pollution, overexploitation, and disease.”*BioScience*,
> > (48):8. 607-615
> >
> > Zavaleta et al. 2001 “Viewing invasive species removal in a
> whole-ecosystem
> > context.” *Trends in Ecology and Evolution, *(16):454-459
> >
>
>
> --
> ******************
> Jono Neiger
> Regenerative Design Group
> 308 Main St, 2C
> Greenfield, Ma 01301
> 413-658-7048
> www.regenerativedesigngroup.com
>
> Conway School of Landscape Design
> Graduate Program in Sustainable Landscape Planning & Design
> www.csld.edu
>
> PINE; Permaculture Institute of the Northeast
> www.thepine.org
>
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